Power-drill.



G. H. GONDIGT.

POWER DRILL.

APPLICATION FILED SEPT. 29, 190B.

Patenigd June 21, 1910.

I/Vii" 4 @9 24 n if" GEORGE HERBERT CONDICT, OF PLAINFIELD, NEW JERSEY,ASSIGNOR TO WILLIAM DULLES, OF NEW YORK, N. Y.

POWER-DRILL.

Specification of Letters Patent.

7 Application filed September 29, 1908. Serial No. 455,301.

To all whom it may concern:

Be it known that I, (haonou llmunnrr CoN- nlo'r, a citizen of the UnitedStates, residing at Plainficld, New Jersey, have invented certain newand useful Improvements in Power-Drills, of which the following is aspecification, accompanied by drawings.

The invention was designed particularly in connection with the wellknown box electric drill, and although it is equally applicable to otherterms of drills, particularly to percussion, I illustrate the preferredform of my improvement in connection with so much of the old and wellknown parts of drill apparatus as is necessary or desirable to show therelation of the improvement thereto.

llollow drill steels have long been used for the purpose of conductingair or water through the duct or bore in the drill steel to the cuttingend of the steel and washing out the accumulating debris so as toincrease the etliciency of the tool by enabling it to act upon the barerock when interfered with by the chips and debris which it forms.

The prime object of the invention is to overcome the tendency of thedrill steel to break after being in use for a short time. Apparentlyeven a slight change of stresses and strains in the drill steel producedby boring a hole at right angles to the drill to conduct the water orcleansing fluid into the central duct of the drill steel is sntlicientto cause the drill steel to break at that point after comparativelyshort use. l have discovered that if the drill steel, which isfurllislled' from the nninufiu-turer with the central duct in it, is notimpaired by any material change of form other than the forging andsharpening of its cutting end, that the defects mentioned are done awaywith. Even the squaring of the rear end of the drill steel to facilitateits being turned while atwork impairs the durability of the steel and inthe preferred form of my invention I entirely avo d such changes.

The preferred form of the invention colltemplates providing the drillsteel with a holder which may be rigidly attached to its rear end andwhich receives the blows of the hammer of the drill. ducts comnnmicatingwith the duct in the drill steel without necessitating any change ormodification of the drill steel. The holder is provided with fluidconnections for This holder has conducting the Water to the drill steelwithout interfering with the rotation of the holder. Preferably .theholder is'provided with a socket for receiving the rear end of the drillsteel and one or more set screws forrigidly securing the drill steel inplace in the holder. Preferably also it is provided with a packingsurrounding the drill steel in the socket for preventing the escape ofwater around the drill steel. Preferably also it is provided with anon-rotating collar containing water-ducts which communicate with thewater duct or ducts in the holder. Preferably also the holder isprovided with a polyhedral portion or other means for engaging anddriving it by the usual rotating gear or chuck member of the drill body.

A preferred example of my improvement is illustrated in the accompanyingdrawings, wherein Figure 1 is a longitudinal central section on the axisof the drill; and Fig. 2 is a detached view of the principal part of theholder.

Av portion of the frame of the drill body is shown at B, the rotatinggear for turning the drill steel holder and drill at O, and the elastichammer cushion at D interposed be tween the two steel washers E.

The drill steel holder is marked H. Its rear end J projects through thecushion D to receive the hammer blows in place of receiving themdirectly upon the drill steel. The portion K of rectangular section isreceived and fits within the rotating member C of the drill body so asto be driven by it, which latter forms a chuck. At L is a splitscrew-threaded sleeve which is screw-threaded onto the portion M of theholder and provides a shoulder for confining the non-rotating sleeve Pof the water supply system. This sleeve P fits upon a smooth portion ofthe holder and is confined bet-ween the loose collars or washers Q whichin turn are confined between the shoulder of the forward end of theholder and the split collar or ring L, which last is secured againstbeing unscrewed by the violent vibration by screwing u) the set-screw R,causing the collar Lto bmd tightly upon its screw-threads. The sleeve 1has an arm T projecting downward and free to play within a hole orbifurcation in a project-mg arm U secured to the frame B of the drill.This arm T prevents any considerable rotation of the sleeve P andPatented June 21,1910.

the drill when the drill is directed down-- ward; or other well knownmeans may be provided for this purpose. The rearward movement of theholder K is limited by the shoulder between the ortions K and M comingagainst the drill body.

The sleeve P is provided with an internal packing W preferably Babbittmetal, which is grooved or channeled at W to form an annular duct, intowhich leads the radial duct W which is enlarged and screw-threaded, asshown, to afford connection with any suitable flexible water supplypipe. In communication with the duct W is a diametrical duct X throughthe axis of the holder. The holder is bored lengthwise to form a soc-ketextendingin the front of the holder and in tersecting the duct X so asto receive water from it. The drill steel Y having the central duct Yapproximately fits the socket of the holder, as shown in Fig; 1, and isrigidly secured thereto by the set screw Z. A packing ring Z in anannular recess, as shown, prevents the water from escaping around theoutside of the drill steel.

Parts of the drill body which do not add to an understanding of-theinvention have been omitted for clearness, such for example as thejournal bearings of the gear-wheel C.

The operation of the apparatus illustrated will be understood. asfollows: The drill steel Y.is inserted in the socket in the positionshown in Fig. 1 and the set-screw Z secures it. The wash water flowingthrough the ducts W" and W passes into the duct X and thence through theduct Y in the drill steel and to the cutting end of the drill. Theholder is rotated by means of the gear wheel C without disturbing thiswater connection, for the arm T prevents the rotation of the sleeve Pwith the holder while allowing all the vibratory movement and dancingthat are necessary to the free and proper action of the drill.

articular and a transverse duct leading to said recess,

means for rotating the holder, means for securing the drill-steel insaid recess, packing for surrounding the drill steel in the recess,

a sleeve mounted on and movable with the holder but free to turnthereupon and having ducts in continuous connection with said transverseduct, means for confining the said sleeve upon the holder, and means forlimiting the rotatory motion of the sleeve.

2. In combination in a drill, a drill-steel holder mounted to allowlongitudinal play and having means for rotatin it, a recess forreceiving the drill steel, an a transverse duct leading to said recess,means for securing the drill-steel therein, packing for surrounding thedrill steel in the recess and a sleeve mounted on and movable with thetool holder but free to turn thereupon and having ducts in continuousconnection with said transverse duct.

3. In combination in a drill, a tool holder having a recess or socketfor the drill steel, and a transverse duct leading thereto, a sleevewhich is carried by and mounted on the tool-holder and has an annularduct in continuous connection with said transverse duct, and a ductleading to said annular duct, means for securing a drill-steel withinthe recess or socket, and packing within the recess for surrounding thedrill-steel.

In testimony whereof I have signed this specification in the presence oftwo subscribing witnesses, September 24th, 1908.

GEORGE HERBERT CONDICT.

Witnesses:

E. VAN ZANDT, E. P. LA GAY.

